1. Field of the Invention
The present invention pertains to the field of aircraft flight control and instrumentation, more particularly to the field of vertical, or pitch axis control and instrumentation.
2. Background of the Invention
Aircraft flight control is a complex activity involving the management of information from numerous instruments that keep track of aircraft flight states including three axes of position and velocity, three axes of aircraft attitude, wind, engine and airframe configuration, flaps, trim. For proper, efficient, and safe flight, the pilot must keep track of and manage all of this information, often in a rapidly changing environment.
A pilot typically manages the vertical axis of an aircraft by reference to a vertical gyro as the primary vertical axis instrument. The vertical gyro presents pitch attitude, which the pilot observes in order to steer the elevator of the aircraft. To maintain level flight and hold altitude, the pilot iteratively adjusts aircraft pitch attitude to a value that is expected to yield the desired flight path and then monitors the altimeter and vertical speed indicator, airspeed indicator and other instruments. As errors creep in, the pilot adjusts the aircraft attitude to fly back to the desired path. Thus, the pilot must constantly monitor the vertical gyro, altimeter, airspeed, and if available, the vertical speed indicator, scanning frequently among them to maintain the desired flight path. Further, the pilot must maintain the pitch axis while maintaining the roll axis, maintaining navigation updates, observing engine instruments, and keeping in radio contact with flight control. Thus, maintaining the vertical axis potentially contributes significantly to the pilots work load and fatigue.
Reducing pilot fatigue and increasing air safety, potentially comes at a cost. Precision aircraft instruments can be expensive to acquire, install, and maintain. Providing flight instruments, even for non-instrument VFR (visual flight rules) flying can improve flight safety by having instruments available for the occasional unanticipated and unavoidable need for instrument flying. Further, air safety can be improved by including redundant instruments, enabling an alternate source of critical information in the case of failure of a particular instrument. Adding redundant instruments, or even equipping an aircraft for instrument flying can be expensive. Thus, techniques that enable the production of low cost flight instruments can materially improve flight safety by encouraging the wider installation and use of flight instruments.
Therefore, there is a need for flight instruments that provide efficient display of flight information to reduce pilot work load and fatigue. Further, there is a need for flight instruments based on low cost sensors to enable higher quality flight control at lower cost, improving overall flight safety.